Telephone-exchange system



Dec; 29, 1 25 4 1,567,041

R. O. COVELL TELEPHONE EXCHANGE SYSTEM Fiied Feb. 28, 1924 2 Sheets-Sheet 1 E MN Wren/off fiwse/l 0. Cave/l.

Dec. 29, 1925- R. O. C OVELL TELEPHONE EXCHANGE SYSTEM 2 Sheets-Sheet 2 Filed Feb. 28, 1924 Patented Dec. 29, i925.

UNE'E'ED STATES Russian 0. GOVELL, or n ncTn'I'c COMPANY, new YORK.

siiinannnerrin, PENNSYLVANIAQASSIGNOR TO WESTERN INCORPORATED, or new YORK, n. Y., A CORPORATION or TELEPHONE-EXCHANGE SYSTEM.

Applicati'onfiled February 28, 1924. Serial No.695,667.

To all 1071052 may concern:

Be it known that I, ll'ossnnn O. COVELL, a citizen of the United (hates of America, residing at Philadeiphia, in the count y' of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Telephone-Exchange Systemsyof which the following is a full clear. concise, and exact description.

This invention relates to a telephone exchange system and more particularly to a system in which connections are established by'mea'ns of machine switching apparatus.

In exchange systems of the above mentioned character it is desirable to enable connections to be established from distant toll points to any subscriber's line in a machine switching exchangearea over the automatic switching mechanism of the exchange. In the establishment of such connections it. is further desirable under certain conditions to signal the local operator in the machine switching exchange in order that such 01- erator may aid the distant toll operator in the obtaining of'con'nections which otherwise might not be establisheddue to lack of proper information or failure of the equipment to respond to the dialing operations of the toll operator. For this purpose a special operators position known 'as theoutw'ard delay operator is associated with the incoming end of the toll line at the machine switching exchange and provision is made for signaling this operator whenever a machine switching sender fails to respond todial pulses from the distanttoll ofliceor when the distant toll operator dials the particular code assigned for calling this outward delay operator. To enable this special operator to be thus called provision ismade in the senders of the machine switching exchange, of'means operative if no impulses are recorded upon the registers of the senders, or if a particular two-digit number is dialed by the toll operator.

It is further desirable in the establishment of toll connections to enable the establishment of calls to other operators positions in the mechanical exchange in addition to the usual calls to the Zerooperator, to the information,repair. long distance or commercial operators. These additional operator "alls are niade in accordance with this invention by dialing codes of two digits only,

the first of the digits always being the digit l These digits through a special organizat on of the sender are both recorded upon a single register preferably the A code reg ister, the translator of the sender being then set in the usual manner from the banks of the single register in accordance with the summation of the two digits recorded. As above intimated one of these special codes. 13, is employed in signaling the outward de 1y operator, in which instance the translator of the sender takes no setting.

It is therefore an object of this invention to provide an improved sender for enabling distant t'oll operators to control the establishment of connections through machine switching exchanges.

A feature of the invention resides in the provision of means in a central oflicc sender for successively registering two digits of a number upon a single register, only when the first of said digits has a particular numerical value.

A further feature of the invention resides in the provision of means for initiating a particular signaling operation in case a special two digit number is registered upon a single register of the sender.

A still further feature of the invention resides in the provision of a circuit local to the sender, for holding the dialing impulse relay of the sender operated for a predetermined interval following the seizure of the sender, for preventing the false release of the relay prior tr. the commencement of dialing. A false release of the rcla might otherwise arise from disturbances in the toll line following its connection with the sender.

These and other features of the invention will appear from a consideration of the drawings and appended claims.

Referring to the drawings, Fig. 1 shows a district selector which may be taken for use by line switches in which incoming toll lines terminate and which may extend connections to a desired district or ollice of the exchange, the control circuits therefor and. in the lower portion of the figure, the sender selector for associating an idle operators sender' with the district selector. Fig. 2 shows as much of a central ol'lice sender as is necessary to an understanding of the invention. In this figure the sender monitor switch is shown in detail in the lower left portion of the figure and in the right portion Ell) of the figure a register steering switch and the A and 13 code registers are illustrated. The numerical registers have been omitted in order to simplify the drawing.

The toll line and associated equipment nd the line switch in which the toll line terminates and which has access directly to the district selector of Fig. 1 have been omitted from this disclosure, being considered unnecessary to a full understanding of this invention. F r a full disclosure of these circuits reference may be had to the application of ll illiam C. Jordan, Serial, No. 080,307, filed December 15, 1923.

The districtselector of Fig. 1 is of the well known power driven panel bank type such as disclosed-in the patent to E. 13. Craft and J N. Reynolds No. 1,123,696, issued January 5, 1915, the circuits of this selector being identical with the circuits of the corresponding selector disclosed in the aforementioned application of .Villiam C. Jordan.

The sender diagrammatically illustrated in 1* 2 is of the general type disclosed in the patent to O. H. Kopp, No. 1,509,434, granted Sept. 23, 1924. Only such portions of the sender have been disclosed as are considered essential to an understanding of the present invention.

The district selector of Fig. 1 may have access to subscribers lines in the machine switching exchange through incoming and final selector switches in the manner fully disclosed in the above mentioned application of William G. Jordan. These switches .have been omitted fromthis disclosure in order that the disclosure may be simplified.

The invention will be best understood from a detailed description of the manner in which a toll connection may be established. It being assumed that the distant toll operator has initiated a toll connection to the exchange area in which the district selector 350 located, she obtains a connection with the idle selector 350 in the manner fully set forth in the above mentioned appli *ation of VJ. C. Jordan. As soon as the district selector is seized by the toll lineswitch a circuit is established which may be tra ed in part from battery, through the winding of sleeve relay 303, terminal 275, and thence to ground at the line switch. Relay 303 upon operating disconnects battery potential from the multiples of terminal by opening the circuit extending from the terminal 220, over the lower contacts of cam 301, the left back contact of relay 302, the outerright back contact of relay 303, the upper contacts of earn 304 to iattery through resistance 305, thus marl:- ing the district selector busy to all line switches having access thereto.

At its inner right front contact relay 303 establishes a circuit for relay 307 which may be traced from battery, through the left winding of relay 307, the left contacts of cam 306, to ground at the inner right front contact of relay 303. Relay 307 upon energizing closes a circuit for advancing sequence switch 310 out of its normal position 1 into position 2, this circuit extending from battery through the magnet winding of'sequence switch 310, the upper left contact of cam 324, the outer left front contact of relay 307 to ground at the right contact of cam 308. As soon as the sequence switch leaves position 1, the original energizing circuit of relay 307 is opened at the upper left contact of cam 306 but relay 307 is maintained energized at this time over a locking circuit extending through its right winding, right front contact, the lower right and upper left contacts of cam 309 to ground. lVith sequence switch 310 in position 2 and relay 307 energized, a circuit is established for starting the hunting movement of the sender selector switch 325 in search of an idle central ofiice sender. The switch starts through the operation of start magnet 311 over a circuit extending from battery through its winding, the back contact of relay 315, the left contacts of cam 308, thence to ground through the inner right front contact of relay 303. Magnet 311, upon energizing, closes an obvious circuit for the rotary magnet 312 of the switch 325, the switch 325 being advanced only until its test brush 313 encounters a test terminal upon which full battery potential is encountered. All idle senders are marked by full battery potential on the multiple test terminals thereof appearing in the banks of all sender selector switches. It will be assumed that the sender shown in Fig. 2 is the first idle sender encountered. When, therefore, brush 313 engages terminal 317 a circuit is established from battery through the back contact of relay 400, terminal 317, brush 313, both windings of relay 314, winding of relay 315 to ground through the lower contact of cam 316. Relay 314 energizes in this circuit but relay 3 does not energize due to the inclusion of the high resistance right winding of relay 314 in series therewith. As soon, however, as relay 314 energizes, it short circuits its own right winding, thereby changing the potential on the multiples of test terminal 317 for marking the selected sender as busy to all sender selectors having access thereto and permitting sufficient current to flow through the winding of relay 315 to cause its energization. lVith relay 315 energized, the circuit of start magnet 311 is opened, whereupon the circuit of rotary magnet 312 is opened and the brushes of the sender selector brought to rest. At its front contact, relay 315 also establis a circuit for relay 313 which may be traced from battery tln'oughresistance "30.3, winding of relay 318,front contact: of relay 315, left contacts of cam 308 to ground at the inner right contact of relay 303. Relay 318 upon energizing locks over its innermost right contact and the inner left contact of relay 319 to ground at the inner right-front contact of relay 303. At its intermediate right armature contacts, relay 318 prepares the fundamental circuit over brushes 326 and At its left front contact, relay 318 establishes a circuit for advancing sequence switch 310 out of position 2 and into position This circuit may be traced from battery, through the winding of sequence switch 310, the lower right and upper left contacts of cam 320 to ground at the left front contact of relay 318. As soon as sequence switch 310 leaves position 2, the holding circuit of relay 307 is opened at the lower right contact of cam 309, and relay 307 thereupon deenergizes.

lVith sequence switch 310 in position 3 and relay 318 energized, a circuit is established for relay 402 of the selected sender and relays 302 and 323 of the district selector. This circuit may be traced from battery, through the winding of relay 323, the upper right and lower left contacts of cam 321, and in parallel therewith from battery through the winding of relay 302 and the lower contacts of cam 321, thence over the outer right contact of'relay 318, brush 322, leftback contact of relay 401, intermediate and left windings of relay 402 to ground. Relay 23 being marginal does not operate in this circuit but relays 302 and 402 operate, relay 302 being functionless at this time. Upon the operation of relay 402, an obvious circuit is established for relay 400 which at its contact removes battery potential from the multiples of test terminal 317, thereby marking the selected sender as busy to all the sender selectors having access thereto. Relay 402 also closes a circuit in parallel with the circuit for relay 400, extending over brush 405 and the normal contact of the bank of monitor switch 450 with which it is associated, to battery through the winding of relay 403, and to battery through the inner right normal contact and winding of relay 404. With relays 403 and 404 both energized, a circuit is established for relay 406 which may be traced from battery, through the winding of this relay, the brush 407 and normal contact of the bank with which it is associated, the right contact of relay 403 to ground at the outer left front contact of relay 404. Relay 406 energizes, closing a circuit from ground, through the outer left front contact of relay 404, the right con tact of relay 403, the brush 407, inner left contact of relay 406, to battery through the back contact and winding of stepping mag net 408. The stepping magnet 403 thereupon energizes advancing the brushes of the switch 450 to their first position terminals, whereupon the circuit of relay 400 is opened at brush 407 and relay 400 deenergizes opening the circuit of magnet 403 arresting the movement of the switch.

pon the energization of relays 404 and 403, a circuit was also estal'ilishedfrom ground over the outer left front contact of relay 404, the right contact of relay 403, the inner left contact of relay 404, conductor 409, brush 328, the lower right and upper left contacts of cam 329, the inner upper oontact of relay 330, to terminal 231, for causing the operation of a signal at the toll operators position to apprise her that a sender has been seized and that she may pio ceed to dial.

At the time relay 404 of the sender energized, it locked itself up, the-circuit extending through its winding and its inner right front contact to ground at the left contact of relay 402, which circuit maintains relay 404 energized after switch 405 leaves position 1 and opens the initial energizing circuit of relays 404 and 403. Relay 403, however, deenergizes as soon, following the advance of switch 450 to position 1, as its slow releasing characteristic permits.

At the time the sender was seized and the district sequence switch advanced into position 3, a dialing circuit was established extending from battery, through the winding of the impulse relay 410 of the sender. over conductor 411, brush 331, the left contacts of cam 332, the lower back contact of relay 330 to terminal 232, this circuit being completed in the manner set forth in the aforementioned application of 1V. C. Jordan. Relay 410 energizes in this circuit. To insure'that relay 410, after being energized. is not disturbed during the period elapsin from the seizure of the sender through the period during which the dialing signal is being transmitted, relay 410 held energized in a local circuit extending through its winding, the right winding of relay 412 and to ground at the left contact of relay 403. This local circuit is, however, opened 'as soon. as relay 403 becomes deenergized.

Upon the energization of relay 410, an obvious circuit is prepared for the slow releasing relay 413. Relay 413 in turn pre pares an obvious circuit for relay 414-. l i ith relays 413 and 414 both energized, the stepping magnet 417 of the first. A. code register is placed under the control of the impulse relay 410.

The operator now actuates her dial in accordance with the first digit of the number of the desired line, this digit being the first code letter of the otiice designation. whereupon the circuit over terminal the lower back contact of relay 330, the left contacts of cam 332, brush 331, conductor 411 to battery through the winding of impulse relay 410 is periodically opened. This impulse relay there-upon follows the interruptions of the dial contacts and effects the setting of the A code register.

Upon the first deenergization of relay 410, a circuit is es 'ablished from ground at its bacl: contact over the left front contact of relay 413, winding of relay 415, brush 416 of the steering switch 425 and the normal contact upon which it is standing, the winding of stepping magnet 417 to battery through the left winding off-normal re lay 418. lilagnet 417 and off-normal relay 418 energize in this circuit, relay 4155 connecting ground over its contactto the olfnorinal conductor 32 for holding the relays 400 and. 404 energized independently of relay 402. Belay 415 also energizes in the circuit of n'iagnet 417 and at its armature and front Contact closes a circuit through the magnet winding 421 of the steering switch 425 preparatory to advancing the steering switch upon the termination of the first series of impulses. A. second circuit is also established at this time for relay 420 which may be traced from battery, through the winding of relay 420, the inner right contact of relay 414, brush 410 and the normal terminal upon which it is standing, the armature and baclr contact of magnet 417, the normal contact and brush 416 of switch 425, thence as traced, through the winding of relay 415 to ground at the back contact of relay 410. Relay 420 energizes in this circuit and at its right contact connects ground directly to the winding of relay 413 to insure that this relay will remain energized until the stepping magnet 41? has completed its stroke. At its left contact, relay 420 connects ground to one terminal of relay 415 for maintaining the relay 415 energized irrespective of the continued deenergization of relay 410. As soon as magnet 417 completes its forward stroke, the circuit of relay 420 is opened and the holding circuits of relay 413 and relay 415 are opened. Thus, the complete energization of magnet 41'? is insured regardless of the period that relay 410 remains deenergized When relay 410 again energizes, the circuit previously traced for relay 415 and magnet 417 is opened and magnet 417 deenergizes, advancing the first code register one step. Relay 415, however, being slow to release does not have time to retract its armature in the brief periods during which relay 410 is deenergized. Thus, in response to each deenergization and energization of relay 410, magnet 417 advances the A code register one step.

Upon the termination of the first series of impulses, relay 410 remains energized for a sufficient time to permit relay 415 to retract its armature, whereupon the circuit of magnet 421 of the steering switch is opened and the steering switch advances its brushes one step. Nith the steering switch in position 1, magnet 422 is operated, in response to the operatioimof impulse relay -10, for advancing the brushes of the B code register to positions corresponding to the digit value of the second code digit dialed. Following the dialing of the code digits of the desired line, the toll operator dials the numerical digits, whereupon the numerical registers, not shown, of the sender are operated to register the numerical designation of the desired line. Followi g the registration of the complete line designation, the traiu'ilz-itor switch, not shown, is set in accordance with the combined settings of the A and B registers in the manner fully set forth in the application of U. H. Kopp hereinbe'iore referred to, and the circuits of the sender are prepared for controlling the setting of automatic switches to extend the connection to the terminals of the desired line. In the preparation of he sender circuits, the sequence switch thereof, the cams of which are illusrated in the upper portion of Fig. 4, is advanced out of its normal position 1. into position 2 preparatory to controlling the district selector 350 in its brush selection movement.

It will be recalled that the sequence switch 310 of the dist "ict selector 350 was advanced to position 3 following the selection of the sender and, tl'ierefore, with the sequence switch of the sender in position 2, a fundamental switch controlling circuit is established between the circuits of the district selector 350 and the sender which may be traced from battery through the right winding of relay 807, the lower contacts of cam 333, contact 356 of relay 818, brush 327, the right back contact of advance relay 401, the windings of the sender stepping relay 430, the b-ac: contact of relay 428, contact of cam 42. winding of polarized overflow relay 424 to ground through the left con-- tacts of cam 420. Relays 307 and 430 ene-rgize in this circuit but relay 424 being polarised does not receive current of the right polarity to cause its operation. Relay 430 upon energizing closes circuit. not shown, in the well known manner for associating a proper pair of counting relays with contacts of the translator switch for controlling district brush selection.

At the district selector, relay 30? upon energizing closes a circuit for advancing sequence switch 310 out of position 3 into position 4, which circuit may be traced from battery, through the magnet winding of the sequence switch, the upper left contact of cam 324, the outer left front contact of relay 307 to ground at the right contact of cam 308. As soon as the sequence switch advances out of position 3, the initial energizing circuit of relay 307 previously traced is opened at the lower left contact of cam 333, but relay 30? is maintained energized in series with the stepping relay 430 oyer a circuit which may now be traced from battery, through the right winding and right front contact of relay 307, the upper left and lower right contacts of cam 333, and thence over the circuit traced to ground, at the lower left contact of cam Y'Vith relay 30? energized and sequence switch 310 in position i, a circuit is estahlished for the up-drire magnet 334: of the switch for adrancin'g the switch shaft in its brush selecting movei'nent. This circuit may be traced from battery, through the winding 01" magnet 33 1-, the lower right contact 01" cam 335, the outer left front con tact of relay 30:- to ground at the right contact or cam As the switch shaft advances in its brush selection movement, the commutator brush 33S engages segments of ooinini tatoi"strip 337, whereupon a circuit is intermittently established in shunt of the winding of stepping relay 30 which may be traced frozn battery, through the right winding of rela 30?,right ii'ront contact of this relay, the upper left contact of cam 333, the upper right contact of cam 336, conunutator strip 33?, brush 338 to ground at the upper left contact of cam 339. Relay 307 is maintained energized over this shuntcircuit but relay 4-30 deenergizes each time that the brush 333 engages a conducting-portion of the strip corresponding to a brush tripping position.

In response to'the intermittent operation 01 relay l30, counting relays ot the sender operate successively in pairs in the well l noun n'l-anner until the O counting relay 5i energizes in parallel with relay 4-28, the rated counting relays locking to ground over the contacts 01 cam 429. lVith relays hit and 423 energized, relay e228 opens the 't'n'iulaniental switch controlling"circuit previously traced and relay 431 establishes a circuit in a well known manner for advancl the sender sequence switch out of position 2 into position e. As soon as thesequence switcl'i leaves position 2, the operated counting relays are released through the opening of the contacts of 0am 4-129. The circuits of the sender are now in condition for controlling the group selection 1hovement of the district selector 350.

At the district selector. upon the opening of the fundamental circuit, relay 307 iileenergizes as soon as the brush 3338 en p ges the nest insulating segment of the commutator strip 337 and at its outer le'tt hack contact establishes a circuit for ad rancing sequence switchZ-llO out or posi tion 4 into position This circuit may be traced from battery, through the magnet winding of sequen e switch 310, the lower left coinaetol can; 32%. the outer left back contact oi" relay 30? to ground at the right contact of earn 308. lsith the sender sequence switch in position +1 and sequence switch 310 of the district selector in position the previously traced fundamental controlling circuit is again established through the windings of sender stepping relay -tl30 and the right winding of rel y 307. Relay 30'? again energizes closthe previously traced locking circuit for itself over the upper left and lower right contacts or cani 333, and advances scquence'switch 310 into position (5. As sequence switch 310 advances from position 5 into position 6, an obvious circuit is closed for the trip magnet 343, extending over the lower right contact of cam 339 for energizing this magnet to trip the selected set of brushes upon the next suhsetpient upward movement of the switch shaft.

With sequence switch 310 in position (3 and relay 307 energized, the previously traced circuit for the up-drivc magnet is again established and the switch shat't 1s driven upwardly. During the first portion oi this upward movement, the selected set oi brushes is tripped through the operation oi magnet 3 3 in the well known manner, and thereafter the tripped set of brushes advances in contact with the terminals of its assoc: .t hank. During the continued up ward movement of the switch shaft. the brush 3-3-1. engages the conunutator strip 3h) 'lor intermittently shunting the stepping re lay 430 of the sender each time that the selccte'l set of brushes approaches the hottom of a group of bank terminals. This shunt circuit may be traced "from battery. through the right winding and right front contact of relay 307, the upper contacts oi? canl 333, commutator strip 3&0, brush 3:1 1 to ground at the upper left contact of cam 33!). Relay 307 is maintained energized over this shunt path but relay 4:30 deencrgizes each time that the brush 34-1 encounters a conducting portion of the strip 340 and in the well known manner causes the successive energization of pairs of counting relays. The operated counting relays are again locked over the contact of cam 42!). As soon as the district brush shaft has advanced to such a position as will satisfy the district group registration of the sender. the 0' counting relay 4:31 energizes in parallel with relay 4:28, the relay 431 :ulvancing the sender sequence switch into pcsition (3. releasing the operated counting relays'and prei iariug the circuits of the sender tor the next selection control. and relay lat the 'liiuidalinental switch controlling cirruit previously traced.

As soon, following the opening of the fundamental circuit, as the brush 34-1. engages the n insulating segment oi commutator strip o-l-O, relay 307 deenergizes opening the circuit of the up-drive magnet 334 and clos- .iiig the previously traced circuit for advancing the sequence switch 310 out of position 0 into position 7. The selected set of brushes has now been positioned in engagement with the lowermost set of terminals in a desired group of its bank.

lVith sequence switch 310 in position 7 relay 307 is energized in a local circuit which may be traced from battery throughits left Winding, the left contacts of cam'306 to ground at the inner right contact of relay 303 and at its outer left front contact closes a circuit for advancing sequence switch 310 out of position 7 into position 8 which may be traced from battery through the magnet winding of the sequence switch, the upper left contact of cam 324, the outer left front contact of relay 307, the upper left contact of cain 308, to ground at the inner right contact of relay 303. As the sequence switch leaves position 7%, the previously traced operating circuit of relay 307 is opened at the upper left contact of cain 306 but if, however, the trunk terminating in the first set of terminals, upon which the brushes are'resting, is at the time busy, as will be assumed, relay 307 remains energized over a locking circuit which may be traced from battery through its right winding and inner left contact, the lower contacts of cam 344, test brush 342 to ground on the test terminal of such first busy trunk. When, therefore, sequence switch 310 reaches position 8, since relay 307 is energized, the previously traced circuit of the rip-drive magnet 334 is established and the switch shaft is driven upwardly in a trunk hunting movement. So long as the brush 342 encounters busy ground potential on the test terminals of the trunks over which it passes, relay 307 will be maintainedenergized and the circuit of the tip-drive magnet will remain closed. When, however, the first idle trunk is encountered, having no ground potential upon the test terminal thereof, the locking circuit of relay 307 is destroyed and as soon thereafter as the brushes are properly centered relay 307 deenergizes opening the circuit of rip-drive magnet 334 and closing the previously traced circuit for advancing sequence switch 310 out of position 8 into position 9. Until the brushes are centered relay 307 held over its left winding, lower left and 307., the lower contacts of cam 306, the right contact of relay 302, this relay having ener' gized, as will be recalled, immediately upon the seizure of the sender, thence over the inner lower back contact of relay 353 to ground at the upper right contact of earn 339. As soon as relay 307 energizes, the previously traced circuit 18 established for advancing sequence switch 31.0 into position 10, or the selection beyond position. From this point the sender functions in the weil known manner to control the further extension of the desired connection. For a description of these functions reference may be had to the above mentioned application of William C. Jordan.

As soon as the last selective control has been exercised by the sender a circuit is established back to the sender traceable in part from brush 345, upper back contact of relay 353, upper right and lower left con-- tacts of cam 354, contact 356 of relay 318, brush 327, right contact of relay 401, windings of relay 430, back contact of relay 428. cam contact 427, winding of polarized relay 424, upper left and lower right contacts of care 426, brush 326, contact of relay 318, lower left and upper right contacts of 0am 355, lower back contact of relay 353 to brush 346. such a direction as to cause the energization of bot-h relays 430 and 424.

Upon the operation of the polarized relay 424, an obvious circuit is closed for relay 401 which opens the fundamental circuit and at its left contact opens the shunt around the right winding of relay 402. The current now flowing through the windings of relay 402 over the circuit previously traced to battery through the winding of relay 302 is now decreased to such an extent that relay 302 deenergizes opening the holding circuit of relay 307 extending through the right front contact of relay 302, where upon relay 307 deenergizes. With relay 307 deenergized, a circuit is now closed for advancing sequence switch 310 out of position 10 into position 11, which circuit may be traced from battery through the winding of sequence switch magnet 310, the lower left contact of cam 324, the'outer left back contact of relay 307 to ground at the right contact of cam 308. In advancing from position 10 to position 11, the previously traced circuit "for relays 430 and 424 The current flows in this circuit in a 5 opened in turn releasing relay 401. With sequence switch 310 in position 11, a circuit is established for the relay 330 extending from battery, through the lower winding of this relay, the upper right and lower left contacts of cain to ground through the left front contact of relay 318, thus opeir ing the tip and ring leads and disconnecting the winding of supervisory relay 359 during the talking selection operation of ti e district selector 350.

A circuit is also established at this time for. relay which may be traced from hattery, through. its right win-ding, the lower contacts of earn 333, contact 856 of relay 31S, brush 827, the back contact of relay 4:01, Winding of stepping relay i550, the hack contact of relay 428, the contact of 0am 4.27, now closed in position 16, the winding of relay 4% to ground over the l ft contacts of cum $26. Relays 307 and 4L0 energize in this circuit, relay 30. closing a circuit from battery through the winding of magnet 310, over the upper left contact of cain 8:24., the outer left front contact of relay 30'? to ground at the right contact of earn 308 for advancing sequence switch 310 out of position 11. After sequence switch 310 leaves position 11, its driving circuit is maintained closed over the upper left contact of cam 308 to the inner right front contact of relay 803 to insure its continued movement through successive talking selection positions. As the. sequence switch continues to rotate, an intermittent shunt is placed around the windings of sender stepping relay 430, extending from battery, through the right winding and right front contact of relay 80? to ground through the lower right and upper left contacts of cam 309. Relay 307 is maintained energized over the shunt path hut stepping relay 4:30

of the sender intermittently deenergizes for controlling the talking selection by successively operating pairs of counting relays at the sender in accorda: cc with the tall:- ing selection registration of the translator switch of the sender. lVhen the sender is satisfied with respect to its talking selection registration. the fundamental circuit is opened through the operation of relay 428 in the well-known manner and the c rcuit of relay 307 is opened. l pon the dcencrgization of relay 307, the circuit of sequence switch magnet- 310 is opened and the sequence switch comes to rest in one of the talking selection positions l2. 14 or 10, for ef-caruple 14. Relay 30'? upon deenergizing also closes a circuit extending from the left terminal of relay 318 over the uppermost front contact of relay 330, the left contacts of earn 360, the outer left back contact of relay 807, the upper left contact of earn 308 to ground at the inner right contact of relay 308, thereby shunting relay 318 and causing deenergization ll ith relay 318 deenergized, the circuit previously traced through the windings of relay 402 and the windings of relays 302 and 323 is opened causing the release of relay l02.

lVhen sequence switch 820 advances out of position 10 the circuit previously traced for relay -l10 is opened at the left contact of own 332, and relay 4:10 thereupon releases, in turn releasing relays 4:13 and 4-H. Relay 413 upon deenergizing, estal'ilishes a circuit from ground at its right nornial contact through brush 435, and the contacts of the restoring haul: of the steering switch back contact and winding of stepping magnet 421, to battery through the right winding of relay s18. Magnet e21 operates in this circuit advancing the brushes of the steering switch to their normal priisitions, the circuit of magnet 4 :21 being interrupted at hrush this when thathriish reachesnornnil. llelay -l-llupon dcent-rgizing estaljilishes a circuit for the stepping magnet til)? of the A register which may he traced from hatlery, through the left winding of relay 418, the winding and contact of magnet 4:17. contacts of the restoring bank and brush 4-112, of the register to ground at the outer right back contact of relay 414. Magnet all? advances the brushes of the register to normal position. in which position the brush it- J3 ere tends the estoring circuit through hrush L34 of the "13 register and the winding of magnet 4-22 to battery. Magnet energizes in this extended restoring circuit, restoring the brushes of the ll register 'lo normal. in a similar manner. the remainin; registers of the sender are restored to normal.

Upon the dccnergization of relay 40?. and. the removal. of ground from the off normal conductor 432 of the sender. the holding circuit of relay 10i opened. This relay dcenergizes, closing a, circuit for relay 406 which may he traced from haltcry through the winding of this relay, brush 4'07 and the off normal contacts of the hanlt with which it is associated to ground at the outer left hack contact of relay 404p. In response to the energization of relay 400. a circuit is ci-tahlishcd from battery. through the ninth ing and hack contact of stepping magnet 10?; of the. monitor switch lit). the inner left contact of relay 100 and thence to ground over brush it and th outer lc'l't l ilt'lx' contact of? relay 404. lrlaguct 408 oner s ng in this circuit, advances the l rushes of the monitor snitch from whatever position they are standing" in at the time into their normal position. in whi l position the circuit of relay -l0tl 1118 net L08 are opened. The deenergiza ion o't relay 402 also closes circuits, not sht. :n. for restoring the remaining apparatus of the sender to nornnil.

and

Since, however, the manner in which this is accomplished does not intimately concern this invention, these restoring operations will not be further discussed or described herein.

Upon the advance of sequence switch 310 of the district selector into position 14, relay 330 is held energized in a circuit which may be traced in part from battery, through its lower winding, the upper contacts of cam 358, the lower front contact of relay 330, termina and thence to ground at the toll ope ators position. Thus relay 330 is maintained energized until the toll operator receives a trunk closure signalasl will hereinafter be described. A circuit is now established for supervisory relay 359 which may be traced in part from battery at the incoming selector, not shown, brush 346, lowermost contact of relay 353, upper contacts of cam 355, winding of relay 359, the upper contacts of cam 35%, uppermost back contact of relay 353, brush 34:5 and thence to ground at the incoming selector. Relay 359 energizes in this circuit and as soon as interrupter 361 makes its right contact, establishes circuit for relay 362. This circuit may be traced from battery through the winding of relay 362, the contact of relay 359, the right contact of interrupter361 to ground over the upper contacts of cam 309. Relay 362 upon energizing, looks over its inner right contact to ground at the right contact of cam 316. The operation of relay 362 initiates operations which result in the release of relay 330, and the lighting of the signal at the toll operators position. The release of relay 330 connects the talking conductors to the back contacts of ringing relay 353 and the lighting of the lamp indicates to the toll operator that the-talking connection has been cut through and that the automatic ringing of the desired subscriber is proceeding.

i /hen the interrupter 361 next makes its left contact, with relay 362 energized, a circuit is established for ringing relay 353 which may be traced from battery, through the winding of relay 353, outer left contact if relay 362, the left contact of interrupter 361, thence to ground through the upper contacts of cam 309. Relay 353 upon energiz ng, establishes a ringing circuit extending to the incoming selector which may be traced in part from the source of ringing current 353 through lamp 371, contacts of cam 364, lower front contact of relay 353, brush 346, and thence through the ringing relay at the incoming selector, not shown, back to brush 3&5 and to ground at the upper front contact of relay 353. Bclay 353 also opens the talking circuit extending back to the toll line and closes the circuit for relay 302 which may be traced from battery, through the winding of re lay 302, the inner upper front contact of relay 353, the right contacts of cam 301, to ground at the left back contact of relay 318. Relay 302 operates in this circuit and looks over its left front contactthrough cam 301 to ground at the left back contact of relay 318. lVhen the interrupter 361 next opens its left contact, the circuit for ringing relay 353 is opened, but relay 302 remains locked. Reference is made to the above identified application of W. C. Jordan for the operation of the ringing relay at the incoming selector and for other operations incompletely described at this time.

Immediately following the initiation of the ringing operation and the deenergization of relay 353, a battery feed coil, not shown, is connected at the incoming selector, across the tip and ring conductors with which brushes 3 1-5 and 3&6 are connected. Relay 359 is again energized closing a circuit for relay 323 which may be traced from battery, through the winding of relay 323, the upper contacts of cam 321, right contact of relay 302, the innermost lower back contact of relay 353, the contact of relay 359, the inner right contact of relay 362 to ground at the right contact of cam 316. Relay 323 energizes in this circuit and closes a circuit for advancing sequence switch 310 into the talking position 15. This circuit extends from battery, through the winding of sequence switch magnet 310, the upper left contact of cam sea, the inner left contact of relay 323, to ground at the right contact of cam 357. As soon as the sequence switch leaves position 14, relay 323 deenergizes, and the circuit of sequence switch magnet 310 is'opened. In position 15, relay 362 is maintained energized in a circuit extending from battery, through its winding, the contact of relay 359 to ground at the upper right contact of cam 339. Relay 302, however, releases as soon as the sequence switch leaves position 14, since its holding circuit is opened at the lower right contact of cam 301.

In response to the answer of the called subscriber, the feed coil above mentioned is disconnected from the tip and ring conductors and relay 359 is again deenergized, opening the circuit of relay 362 which causes the extinguishing of the signal at the toll operators position to indicate that the called subscriber has answered. The release of relay 362 also closes a circuit for again energizing relay 323, this circuit extending from battery, through the winding of relay 323, the upper contacts of cam 321, inner left back contact of relay 362, the upper contacts of cam .301 and thence to ground at the left back contact of relay 318. Relay 323 now locks over its inner right contact to ground at the lower left contact of cam 339,

Release of the connection.

Upon the termination of the conversation, the battery feed coil above mentioned, is again connected across the tip and ring conductors. Relay 359 operates, in turn operating relay 362, causing the illumination of the lamp at the toll operators position. The toll operator then removes her plug from the jack releasing the line switch which removes ground from terminal 275 releasing relay 303. The release of relay 303 closes a circuit from ground at its inner right back contact over the right contacts of cam 320, to battery through the winding of sequence switch magnet 310 for advancing the sequence switch into position 18. As the sequence switch leaves position 15, the locking circuit of relay 323 is opened and this relay releases. IVith sequence switch 310 in position 18, a circuit is closed for down-drive magnet 365 extending from battery, through the winding of magnet 365, the lower left and upper right contacts of cam 320 to ground at the inner right contact of relay 303. Through the operation of magnet 365, the

' switch shaft is driven downwardly into normal position where brush 341 engages normal segment 366 closing a circuit for advancing sequence switch 310 into normal position. This circuit may be traced from battery, through the magnet winding of se quence switch 310, the lower right contact of relay 324, segment 366, brush 341 to ground at the upper left contact of cam 339. hen the sequence switch 310 leaves position 17, ground is removed from brush 342 at the left contacts of cam 309, initiating the release of the incoming and final selectors for which operations reference is made to the above identified application of W. C. Jordan.

Specal calls to outward delay operator.

If for any reason the toll operator should desire to connect with the outward delay operator at the office at which district selector 350 is located, she would, after connecting with that oifice and receiving the dial signal, dial a code 13. In response to the dialing of the first digit 1, the A register is advanced to its first position as previously described, following which the register steering switch 425 advances to position 1. A circuit is now established for relay 423 extending from battery, through the winding of this relay, contact- 446 and brush 445 of the A register, to ground at the contact of relay 415. Relay 423 energizes, locking over its inner left contact to ground at the inner left contact of relay 414. The second series of impulses which would normally operate the stepping magnet 422 of the B register, now operates magnet 417 of the A. register, The stepping circuit of magnet 417 extends from battery, through the left winding of relay 418, winding of mag net 417, outer left front contact of relay 423, brush 416, winding of relay 415, left front contact of relay 413 to ground at the back contact of relay 410. Relay 423 also transfers the circuit of relay 420 for controlling complete stopping of the register magnet from the circuit of magnet 422 to the circuit of magnet 417. Thus the A register receives both series of impulses, and since the digits dialed are 1 and 3 respectively, takes a setting corresponding to the sum of the two digits or to position 4. In position 4, a circuit is established for relay 442 extending over contact 447 and brush 448, outer right contact of relay 423 to ground at the inner left contact of relay 414. Relay 442 upon energizing establishes a circuit from ground at its contact over brush 326, the next to the outer contact of relay 318, the lower contacts of relay 355, (the sequence switch of district selector 350 standing in position 3 at this time), terminal 296, and thence to battery through the winding of a relay, at the outward delay operators position lighting a lamp thereat, to signal that operator as fully set forth in the application of'iV. C. Jordan. The operation of this relay also causes the removal of ground from terminal 27 5 releasing relay 303. The release of relay 303 closes a circuit extending from ground over its inner right back contact, the right contacts of cam 320 to battery through the winding of sequence switch magnet 310 for advancing the sequence switch into position 7. In position 7 sequence switch 310 is advanced to position 8 over a circuit extending .from battery, through the magnet winding of sequence switch 310, the lower right contact of cam 324, normal segment 366, brush 341, to ground at the upper left contact of cam 339. As soon as the sequence switch reaches position 8, since the relay 307 is not operated, a circuit is immediately established from battery, through the winding of sequence switch magnet 310, lower left contact of cam 324, the outer left back contact of relay 307 to ground at the right contact of cam 308 for advancing the sequence switch into position 9. In position 9, the circuit previously traced through the lower right contact of cam 324 is again established for advancing the sequence switch into normal position. As the sequence switch leaves position 11, the circuits through relays 410 and 402 of the sender are opened and the sender releases as previously described. The outward operator noting the lighting of the lamp may communicate with the distant toll operator by means of the multiple of the trunk line to which the signal operated is individual.

Connections to other operators, such as the repair clerk, information operator, ctr,

are also represented by codes beginning with 'the digit 1; however, any cod other than iiigna lz'ng the operator upon the permanent signal condition at the sender.

It will be recalled that at the time the sender was seized, the monitor switch 450 1 the sequence switch of district selector 350 advances out of position 10 releasing relays 410, 413 and 414, a circuit is established for wipe-out relay430 extending from battery through the winding of this relay, over brush 440, the right front contact of relay 404, the left normal contact of relay 413 to ground at the back contact of relay'410. Relay 439 upon operating, causes the release of the sender in the well known manner.

If the operator does not wipe out the connection, the monitorswitch 450 advances out of position, '1 under the control of the slow interrupter 436 provided the operator does not immediately dial the first digit of the wanted line designation. The circuit for advancing switch 450 may be traced from battery, through the winding of magnet 408, interrupter 436, No. 1 contact and brush 438 of switch 450 to ground at the right contact of relay 406. When switch 450 reaches position 3, if relay 406 is still deenergized,.the switch is immediately advanced into position- 5 over a circuit extending through the wind ing and contact'of magnet 408, the No. 3

and No. 4 contacts and brush 438 of switch 450 to ground at the right contact of relay 406. In position 5, a circuit is established from battery through the winding of relay 442, the No. 5 contact and brush 441 of switch 450 to ground at the outer left contact of relay 406. Relay 442 uponenergizing, closes a circuit as previously described to bring about the lighting of the lamp corresponding to the trunk used in th connec-- tion at the outward delay operators position and initiates the release of the district selector and the sender.

If the sender fails to release, and there fore the monitor switch is not restored to normal,- it will continue to count off time, advancing from position 5 into position 6 under the control of magnet 408 and interrupter 436 over the circuit previously traced. In position 6, a circuit is then established from ground at the outer left back contact to relay 406, brush 441, to battery through lamp 451, signaling the monitoring operator that a permanent signal condition exists and that the sender has not released. If the toll operator starts dialing before switch 45.0

through the winding of this relay, brush 443,

to ground through brush 444, and switch 450 will, therefore, be immediately advanced into position 7 over a circuit extending from ground at brush 444 thence over brush 443,

inner left contact of relay 406, to battery through the contact and winding of stepping magnet 40S, and no signal will be given the outward operator, nor will the sender be released. I

Vi hen sequence switch 450 advances from positions 6 to position 7, the circuit for relay 406 is opened and that relay releases. if the operator completes dialing, register switch 425 again closes the circuit of relay 406 operating that relay. If, however, the operator fails to complete dialing and relay 406 remains deenergized due to that fact, switch 450 is advanced from position 7 to position 9 under the control of interrupter:

436; Upon reaching position 9, switch 450 advances at once into position 10 by reason of the self-interrupting circuit through magnet 408 and its back contact, brush 438, and the right contact of relay 406. In position 10, a short circuit is closedaround, the left winding of relay 402, over brush 441, and the outer left back contact of relay 406, increasing the current flowing through relay 402 and relay 323 to such an extent as to cause the energization of marginal relay 323. The energization of relay 823 results in advancing the district selector to tell-tale" position in which position the toll operator is given a signal to indicate that a stuck sender conditionexists, whereupon the toll operator restores the connection releasing the district selector. Reference is made to the above identified application of W. C. Jordan for a more complete description of this operation.

Had dialing been completed or the sender functioned correctly, then when the monitor switch 450 reached position 7, relay 406 would have been operated over brushes 443 and 444 and the switch450 would have advanced at once into position 12. If the sender fails to release under the stuck sender condition, when switch 450 reaches position 11, the circuit of lamp 451 is again established indicating to the monitoring operator that the sender has failed to release. Since the remaining functions of the monitor switch do not directly concern the present invention, they will not be further described herein.

W hat is claimed is 1. In a registering system, a pair of registering devices, a control circuit, means for normally extending said control circuit to rid registering devices in succession, means operated over said control circuit for posisaid first registering device in a particular position-to transfer the extenslon of said control circuit from the second registering device back to the first registering device whereby said first registering device may be further positioned.

2. In a registering system, a pair of registeringdevices, a control circuit, means for normally extending said control circuit to said registering devices in succession, means Operated over said control circuit for positioning said registering devices, and a relay operated in response to the positioning of said first registering device in a par ticular position to transfer the extension of said control circuit from the second registering device back to the first registering device whereby said first registering device may be further positioned.

In a registering system, a pair of registering devices, a control circuit, a steering switch for normally extending said control circuit to said registering devices in succession, means operated over said control cir cuit for positioning said registering devices, and means operated in response to the positioning of said first registering device in a particular position to transfer the extension of said control circuit from the second registering device back to the first registering device whereby said first registering device may be further positioned.

4.. In a registering system, a pair of registering devices, an impulse relay, a control circuit controlled thereby, means for normally extending said control circuit to said registers in succession, means operated over said control circuit for positioning said registering devices, and means operated in response to the positioning of said first registering device in a particular position in response to the first series of impulses received by said relay to transfer the extension of said control circuit from said second registering device back to the first registering device whereby said first registering device is also further positioned in response to the second series of impulses received by said relay.

5. In a registering system, a pair of registering devices, a control circuit, a steering switch for normally extending said control circuit to said registering devices in succession, means operated over said control circuitfor positioning said registering devices, acircuit closed in successive positions of said switch for insuring complete positioning of said registering devices, and means operated in response to the positioning of said first registering device in a particular position to transfer the extension of said control circuit from the second registering device back to the first registering device and to transfer said second circuit from the second registering device back to the first registering device.

6. In a registering system, a pair of registering devices, operating magnets therefor, an impulse receiving relay, a quick acting relay, a control circuit controlled by said impulse relay, a steering switch adapted in successive positions to extend said control circuit in parallel through said quick acting relay and said operating magnets, a circuit for said magnets controlled at contacts of said quick acting relay, means controlled by said magnets when completely energized to open the circuit of said quick acting relay, and means operated in response to the positioning of said first registering device in a particular position to transfer the extension of said control circuits from the magnet of the second registering device back to the magnet of the first registering device whereby said first registering device may be further positioned and to transfer the branch of said control circuit extending through said quick acting relay from connection with the mag tcring devices, a control circuit, means for normally extending said control circuit to rid registering devices in succession, means operated over said control circuit for positioning said registering devices, means operated in response to the positioning of said first registering device in a particular position to transfer the extension of said control circuit from the second registering device back to the first registering device whereby said first registering device may be further positioned, and means operated in response to the combination of the first positioning and a particular second positioning of said first registering device for establishing a special signaling circuit.

8. In a telephone exchange system, an incoming line, a register sender, means for associating said sender with said incoming line, a relay in said sender, means for establishing a pulsing circuit over said incoming line and including said relay, and means for establishing a second circuit for said relay to render said relay unresponsive to disturbances on said incoming line.

9. In a telephone exchange system, an incoming line, a register sender, means for as sociating said sender with said incoming line, a relay in said sender, means for establishing a pulsing circuit over said incoming line and including said relay, and means for establishing a second circuit for said relay during a predetermined interval to render said relay unresponsive to disturbances on said incoming line.

10. In a telephone exchange system, an

"incoming "line, a register sender, means for associating said sender with said incoming line, a relay in said sender for establishing a pulsing circuit over said incoming line and including said relay, a slow releasing relay, means for closing and opening a circuit for said slow releasing relay to establish a holding circuit for said relay for a predetermined interval to render said first relay unresponsive to disturbances on said incoming line.

11. In a telephone exchange system, an in coming line, a register sender, means for associating' said sender with said incoming I line, a relay in said sender, means for establishing'a pulsing circuit over said incoming I line and including said relay, a slow releasing relay, a timing device, means under the control of said timing device for closing and 20 opening a circuit for said slow releasing relay to establish a holding circuit for said first relay for apredeterinined interval to render said first relayunrespon'sive to disturbances on said incoming line.

12. In a telephone system, an incoming line, a register sender, means for associating said sender with said incoming line, a relay in said sender, means for establishing a pulsing circuit over said incoming line and including said relay, and means operative upon the association of said sender with said line for establishing a temporary holding circuit for said relay to render said relay unresponsive to disturbances on said incoming line.

In witness whereof, I hereunto subscribe my'name this 25th day of February A. 1)., 1924.

RUSSELL O. COVELL'. 

